Spinning device



Jan. 5, 1965 Y. JUILLARD 3,163,976

SPINNING DEVICE Filed May 14, 1963 2 Sheets-Sheet 1 Jan. 5, 1965JUILLARD 3,163,976

SPINNING DEVICE Filed May 14, 1963 2 Sheets-Sheet 2 United States Patent3,163,975 Patented Jan. 5, 1965 3,163,976 SPHNNING DEVHIE Yves Jniliard,Mulhouse, Haut-Rhin, France, assignor to Societe Alsacienne deConstructions Mecaniques, Muihouse, Haut-Rhin, France, a company ofFrance Filed May 14, 1963, Ser. No. 2250,25 2 Claims priority,appiication France May 25, 1%2 11 Ciaims. (Cl. 57-583?) This inventionrelates to a novel device for producing spun yarn from a sliver or roveof fibre. While various methods and apparatus have heretofore beenproposed for the manufacture of yarn from slivers of relatively shortfibre otherwise than by means or" a conventional spinning frame, by thegeneral process of disintegrating the sliver and then recombining thedisintegrated fibre into a continuous yarn, none of these priorproposals have met with any degree of commercial success, partly owingto the complication of the mechanism suggested.

The present invention is based on the discovery of a novel device bywhich disintegrating of the sliver or rove and recombining thedisintegrated fibre into a continuous yarn can be performed in anunexpectedly simple and efiective manner by the application of pneumaticforces coupled with dynamic forces capable of being produced by verysimple machinery involving a minimum of moving parts.

Gbjects of this invention include the provision of a new device forproducing spun yarn by the direct disintegration of sliver or rove andrecombination of the disintegrated fibre into a continuous yarn ofextremely satisfactory textile characteristics; the provision of such amethod relying primarily on the effect of an airstream for shredding thefibre; the provision of such a method wherein the spun yarn grows byaccretion at one end thereof through the pick-up of loose fibre spreadover a surface in motion relative to said end; the provision of novelspinning apparatus of very simple and economical design, maintenance andoperation, wherein the only moving part is a spinning rotor; and broadlythe Provision of method and means for producing high-grade spun yarn ina more effective and generally satisfactory way than was heretoforepossible.

Broadly, the spinning system of the invention comprises feeding a sliveror rove of short fibre to a receiving surface while exposing the sliverto an airstream to shred the sliver and project the shredded fibre in anevenly spread layer upon said surface, displacing the tip of a yarnrelative to said surface in contact engagement with the layer of fibrethereon and drawing said yarn away at a rate correlated with the rate offeed of the sliver to the surface,'whereby the tip of yarn will pick-upfibre from said layer and grow by accretion to form spun yarn as acontinuous extension of the yarn initially provided.

In accordance with an important feature of the invention, a secondairstream is discharged in opposition to the first airstream so as tocreate a neutral boundary layer at the meeting of both airstreams, andthe airstreams are regulated relative to each other to position saidboundary layer intermediate the sliver and the yarn so as to separatethem effectively by purely pneumatic means.

In a preferred embodiment of the invention, the receiving surface is theperipheral wall surface of a cavity defined in a rotor, the rotation ofwhich serves to draw in air axially through passages at both ends of thecavity to produce said airstreams and discharge them radially outward bycentrifugal force, simultaneously projecting the shredded fibre bycentrifugal force against the peripheral surface of the cavity.

Two exemplary embodiments of the invention will now be described forpurposes of illustration but not of limitation with reference to theaccompanying drawings,

wnerem:

FIG. 1 is a simplified view in axial section of spinning apparatusaccording to a first embodiment of the invention;

FIG. 2 is a transverse cross section made on the line 11-11 of FIG. 1;

FIG. 3 is a view generally similar to FIG. 1 illustrating a modifiedembodiment; and

FIG. 4 is a section on the line IV1V of FIG. 3.

The spinning apparatus illustrated in FIGS. 1 and 2 comprises aconventional feeder device consisting of a pair of rolls 11 and 12adapted to feed a rove or sliver It made up of short discontinuoustextile fibres to a stationary inlet nozzle 2, thence into the innercavity of a revolving rotor or turbine 3, whence the yarn issues througha stationary outlet nozzle 4 to a delivery device comprising a pair ofrolls 5-6. The entire system is shown in this embodiments as disposedvertically.

The input or feeder device comprising the pair of rolls 11, 12 mayconveniently constitute the output or delivery rolls of a conventionalroving apparatus delivering a continuous strip of short fibres, free ofany twist (and constituting a sliver), or provided with a minimum amountof twist to impart some stiffness thereto (i.e. a rove). This sliver orrove is then guided through the inlet nozzle 2 which is in the form of asimple cylindrical tube.

The turbine 3 comprises a rotor in the form of a generally fiat diskdefining an inner cavity having its radially outer periphery bounded byan annular trough 14. The rotor 3 is here shown as supported forrotation about the outlet nozzle 4, in alignment with the inlet nozzle,by means of spaced ball bearings 15 and 16 having their inner racessecured to said outlet nozzle 4 and their outer races secured in a bore17 of a hub or nose 18 projecting downwardly from lower wall 312 of therotor.

The lower end portion of the hub 18 is defined by a pulley 19 forconnection by way of a drive belt 21 with any suitable source of kineticpower. The lower wall 312 of the rotor is formed with an annular seriesof holes 24 adjacent to the trough 14 but along a radius smaller thanthe maximum radius of said trough. Similarly, upper wall 3a is formedwith an annular set of holes 25 positioned approximately on acircumference of equal radius to the series of holes 24.

The lower or outlet end of the inlet nozzle 2 extends through a hole 27formed axially in the upper wall 3a of the rotor, with sufiicientclearance to avoid objectionable friction.

The inner wall surface of the trough 14 is arranged to facilitateslipping of the fibres thereover as will be more fully described later,and is advantageously for this purpose provided with a highly smoothsurface finish. It should be noticed however that the important point inthis respect is that the wall surface shall not oppose any resistance tothe fibres in the circumferential direction.

It may already be noted that in the operation of the system as presentlydescribed, the revolving rotor 3 functions as a two-way suction pump,with air being continuously drawn in axially both through the inletnozzle 2 and the outlet nozzle 4 into the cavity of the rotor, anddischarged by centrifugal force radially outwards across the cavity andout through the peripheral holes 25 and 24 respectively. An annularseries of radial blades 23 is shown provided in this embodiment adjacentthe holes 24 to increase the rate of discharge of the air therethrough.

The operation of the system will now be described, it being firstassumed that the apparatus has previously been primed in a manner laterdescribed, so that spun yarn 30 is already present in the cavity of therotor and extends as shown through the outlet nozzle 4 out of which itis being drawn at a certain rate by the action of the delivery rolls5-6. Simultaneously, the input rove or sliver is being fed into thecavity by way of the input nozzle 2 at a rate determined by the inputfeed rolls 11 and 12. As the sliver advances downwards through thenozzle 2 it is exposed to a violent shredding action from the air whichis simultaneously being drawn at a high velocity down through saidnozzle, so that at its entry into the cavity of the rotor 3, the fibreis in a loose, disintegrated state in suspension in the air entrainingthe same.

This mixture of air and shredded fibre entering the rotor cavity issubjected to the concurrent actions of centrifugal force and frictionagainst the inner surface of the upper wall 3a. Each air molecule isdriven outward at alinear velocity that increases continuously from thecenter to the periphery of the rotor, with its angular velocityincreasing concurrently from zero at its point of entry into the rotorto a maximum equal to the angular velocity of the rotor 3 itself as itstrikes the surface of the peripheral trough 14. As a consequence, theair molecules describe outwardly spiralling paths, and impartsubstantially identical spiral paths to the particles of textile fibresuspended in the airstrearn as indicated schematically by thediscontinuous spiral lines in FIG. 2.

It will thus be understood that the shredded fibres stripped from thesliver It in the input nozzle 2 are introduced in the form of aspread-out shower into the upper part of the rotor cavity.

As previously mentioned, there are two airstreams entering the rotorcavity through the two axial nozzles 2 and 4 and issuing out of thecavity through the series of. holes 25 and 24 respectively. It has beenfound that with this arrangement the two airstreams impinging againstone another at the horizontal Inidplane of the rotor cavity create inthe area of said midplane a neutral or boundary layer which veryeffectively prevents any mingling between the shredded input fibre inthe upper part of the cavity and the yarn being formed in the lower partof the cavity. The thin boundary layer of air substantially on themidplane P of the rotor cavity constitutes in effect a non-material buthighly effective separating partition dividing the cavity into an upperor inlet chamber A and a lower or outlet chamber B.

The spreading shower of shredded fibres entering into the upper chamberA and spiralling outwards therein along the upper wall 3a retain theirgeneral orientation throughout their spiral paths owing to the action ofthe expanding air medium in which they are entrained. That is, the headend of each fibre reaches the peripheral trough surface first, and asthat surface is revolving at an angular velocity higher than the fibreend, the remaining length of the fibre is then forcibly applied againstthe trough surface, so that the fibres are laid down in an extended orstretched condition and with a regular circumferential orientationover'the bottom of the trough, i.e. along the maximum-diameter regionthereof. In other words, all the fibres are lying more or less straightand taut rather than any of the same tending to curl or loop. Thisuniform, homogeneous distribution of the fibres provides an ef ectsimilar to drawing or doubling and imparts great regularity to theresulting yarn. This may perhaps be further understood by the followingexplanation. Any unevenness present in the input sliver, over a length ltherein, will as a result of the centrifugal spreading action describedabove be finally distributed over a length all in the finished yarn.with D being the outer diameter of the rotor trough l4. Simultaneouslyand by the same token, the initial unevenness or irregularity whateverits nature, e.g. a local thickening or restriction in the input sliver,will be attenuated in a corresponding ratio 1/ 1rD.

As centrifugal pressure maintains the fibres firmly applied against thesurface of the trough 14-, the airstream is discharged through the holes25 while leaving the fibre in place.

As indicated above, it is temporarily assumed that previously formedyarn 34 is present in the lower chamber B of the rotor cavity, and isbeing drawn out by rolls 5, 6 through the output nozzle 4. The upperstretch of this yarn 38 extends across the lower wall surface 31') ofthe rotor and its outer end sweeps across the bottom of the trough 14,while rolling or spinning in a direction imparted by the rotation of thewall 3.5, ie in the direction indicated by arrow f2 in FIG. 2 where itis assumed that the rotor is revolving in the direction of arrow fl. Asit sweeps and rolls around the trough 14, the end of the yarn 3i picksup the loose fibre present over that surface.

Assuming the angular rate of the rotor is wl, which of course is alsothe angular rate of the fibres firmly applied against the outer wall ofthe rotor by centrifugal pressure, it is found that the angular velocityof the outer end of the yarn 3% assumes a value W2 somewhat higher thanW1, and the precise value is determined by the draft velocity impartedto the yarn by the output rolls 5-6. Thus the outer end of the yarn 30sweeps around the periphery of trough 14 at a relative velocity (w2w1),so that it continually sweeps and picks up the incoming fibreprogressively as the latter are deposited around the trough wall, andthe yarn thus grows continually by accretion.

As earlier noted, during the sweeping action performed by the outer endof the yarn 3d, the loose incoming fibre entering the upper part A ofthe rotor cavity are maintained positively isolated from the yarn 30 inprocess of formation in the lower space E of said cavity, by thenon-material partition constituted by the flat neutral zone or boundarylayer P at which the rising and descending airstreams meet.

In order to prime the apparatus at the start of a spinning run, therotor 3 is set into rotation and an input sliver is fed into its cavityby means of the input rolls ll, 12 and input nozzle 2, until a layer ofshredded fibre has been deposited around the surface of trough 14 in themanner described above. A previously formed yarn 3a? is then slowlyinserted, preferably manually, up through the outlet nozzle 4 whereuponthe rising airstream fiow ing through said nozzle will sweep up theinserted yarn and promptly deliver it into the rotor cavity until itsupper end engages the outer surface of trough 34, when the action of therising airstream on the yarn will cease, and the inserted yarn willstart rotating with the rotor and its outer end beginning to sweep upthe yarn present in the trough 14 as earlier described. The output rolls5-6 can then be started in motion to draw out the spun yarn downwardlythrough nozzle 4 and no further manual interventions are required. Theouter end of the yarn 3% will immediately start to grow through thecontinual and progressive accretion of yarn thereto, and freshly spunyarn will be continually available at the output nozzle 4 and rolls 56so long as sliver is being fed into the apparatus.

The thickness of the resulting spun yarn depends essentially only on therelation between the input feed rate of I the sliver and the yarn outputrate imparted by the delivery rolls 5-6, assuming a correct angular rateis imparted to the rotor 3. It will readily be understood that thehigher the ratio of input to output feed rate, the thicker the spun yarnobtained. Conversely, if the output feed rate is increased in relationto the input feed rate, the yarn delivered at the output of the devicewill be increasingly thin, and should the relative increase in outputrate be continued beyond a certain point, the apparatus will beunprimed.

It will be noted that the input feed rolls 11, 12 may be considered asthe input rolls of a yarn drawing system, wherein the draft rolls arereplaced by the suction applied to the fibre in the input nozzle 2 ofthe turbine. To ensure that the fibre will be in a loose condition attheir entry into the rotor cavity, as is required, it is clear that thewhole length of each fibre should at that point have moved past thepinch point or nip of the input rolls. Thus the distance from said nipto the entrance of the rotor cavity should be somewhat longer than themaximum length of the fibre encountered in the sliver or rove to beprocessed.

On the other hand, it is also desirable to avoid the condition in whichthe fibre after being shredded and disintegrated in the input nozzlewould tend to recombine more or less in bunches over the latter part ofthe path through said input nozzle to the rotor cavity. This conditionimposes a maximum value to the length of the input nozzle 2. Tests haveshown that satisfactory results are obtained when the input nozzle 2 hasa length approximately equal to 1.3 times the maximum length of freefibres in the sliver material being treated.

As regards the radial dimensioning of the turbine 3, it will beunderstood that this should be large enough to enable each individualfibre to stretch out in full across the radial extent of the upper wall3a. With this consideration in mind it is found that the inner radius ofthe turbine cavity can satisfactorily be made to equal about 1.2 timesthe maximum length of the fibre being treated.

Further, the diameter of the input and output nozzles 2 and 4 inrelation to the length thereof should be so determined that the loss ofair pressure occurring therethrough or flow resistance opposed therebyto the respective airstreams, shall substantially balance each other, sothat the neutral zone P in which the two airstreams op pose each otherand provide the non-material partition etween the rotor cavity chambers,will be properly positioned substantially on the central transverseplane of the rotor cavity.

As to the axial length of the rotor cavity of the turbine 3, this shouldbe large enough to provide sufiicient depth in each of the chambers Aand B for the necessary motion of the fibres therein and also to ensurethat the position of the neutral partition zone P separating saidchambers will not be too critical in view of the considerations ofaerodynamic balancing stated in the foregoing paragraph. However, anupper limit to said axial length is set by the condition that theairstrearns should not be subjected to a reduction in velocity so greatas to prevent the setting up of a stable boundary layer P capable ofacting as an effective partition between the two chambers. In practice,it is found that the various conditions indicated above are quite easilymet and that the dimensioning of the apparatus described is notespecially critical for successful operation.

In the embodiment of the invention described with reference to FIGS. 1and 2, it was stated that the angular speed w2 of the tip of the yarn353 in process of formation was somewhat greater than the angular speedwl of the rotor and hence of the layer of loose fibre therein. This isnot essential however, and in other embodiments of the invention anexample of which will be described with reference to FIGS. 3 and 4, therelationship between the tent as a frustoconical surface 41 with aradius decreasing upwardly, rather than being formed with thesemi-circular contour shown in FIG. 1. Moreover, the lower wall of rotor49 is formed with an annular recess 42 near its outer periphery, theradially outer surface of this recess being provided as a frustoconicalsurface 43 of inverse, taper from that of the surface 41. As shown inFIG 3, the dimensioning is such that horizontal segment 44 of yarn 45 inprocess of formation bridges the annular recess 42 and engages the outerwall surface of the rotor cavity substantially at the base of theupwardly tapering surface 41. It is found that with this arrangement,owing primarily to the upwardly decreasing radius of the surface 41 inthe region of engagement of the outer tip of the yarn tithe yarn tendsto assume an absolute angular velocity w2 somewhat smaller than theangular velocity wl of the rotor, contrary to what was true in the firstembodiment. Otherwise stated, whereas in the first embodiment the tip ofthe yarn 30 picks up the deposited shreds of fibre from the rear of thedeposit or in trailing relation with reference to the direction ofrotation, in the embodiment of FIGS. 3 and 4 the yarn picks up fibrefrom the front of the deposit or in leading relation. In FIG. 4, thedirection of fibre pick-up by the tip of the yarn being spun, isindicated by the arrow M which corresponds tothe sense of relativerotation of the yarn with respect to the rotor and fibre. Itis notedthat the direction of twist imparted to the spun yarn, as indicated bythe arrow f3 in FIG. 4, is the sarne as in the case of the firstembodiment.

When priming the apparatus of FIGS. 3 and 4 it is found that the primingoperation is facilitated if the initial yarn is inserted through theoutlet nozzle 4 quickly rather than slowly as was the case in the firstembodiment.

Various embodiments of the invention other than the two illustrated anddescribed herein may be conceived within the scope of the invention.Thus the configuration of the inner rotor cavity, the manner ofrotational support of the rotor, as well as other mechanical features,may be modified in various ways. The basic principles of the novelspinning process may be embodied in apparatus using means other thancentrifugal force forv creating the airstream and projecting the fibreagainst the receiving surface.

I claim:

1. A device for spinning yarn comprising a rotor having a cavitydefining two opposite parallel flat sides and a peripheral surface ofrevolution; means for rotating the rotor; the rotor having axialpassages of substantially the same diameter connected to said oppositesides thereof and communicating with said cavity; the rotor havingperipheral aperture means communicating with the cavity whereby rotationof the rotor will draw in air through both passages into said cavity anddischarge said air through said aperture means by centrifugal forcethereby creating opposed airstreams meeting on a transverse plane ofsaid cavity to establish thereat two boundary layers separated by aneutral pressure zone; means for feeding a sliver of fibre through onepassage into said cavity for shredding by the related airstream andprojection of the shredded fibre against said peripheral surface as anevenly spread layer; and means-for drawing spun yarn from said cavitythrough the other axial passage, said spun yarn growing by accretion atits extremity engaging said surface through pick-up of fibre thereat,and said neutral pressure zone acting to separate said yarn from theincoming fibre.

2. A device for spinning yarn comprising a rotor having a cavitydefining two opposite parallel sides and a peripheral surface ofrevolution; means for rotating the rotor; the rotor having axialpassages of substantially the same diameter connected to said oppositesides thereof and communicating with said cavity; the rotor having anannular series of apertures provided in the opposite sides thereof nearthe periphery communicating with the cavity whereby rotation of therotor will draw in air through both passages into said cavity anddischarge said air through said apertures by centrifugal force therebycreating opposed airstreams meeting on a transverse plane of said cavityto establish thereat two boundary layers separated by a neutral pressurezone; means for feeding a sliver of fibre through one passage into saidcavity for shredding by the related airstream and projection of theshredded fibre against said peripheral surface as an evenly spreadlayer; and means for drawing spun yarn from said cavity throughthe otheraxial passage, said spun yarn growing by accretion at its extremityengaging said surface through pick-up of fibre thereat, and said neutralpressure zone acting to separate said yarn from the incoming fibre.

3. A device for spinning yarn comprising a rotor having a cavitydefining two opposite parallel sides and a peripheral surface ofrevolution; said peripheral surfaces having a semi-circular crosssectional contour; means for rotating the rotor; the rotor having axialpassages of substantially the same diameter connected to said oppositesides thereof and communicating with said cavity; the rotor havingperipheral aperture means communicating with the cavity whereby rotationof the rotor will draw in air through both passages into said cavity anddischarge said air through said aperture means by centrifugal forcethereby creating opposed airstreams meeting on a transverse plane ofsaid cavity to establish thereat two boundary layers separated by aneutral pressure zone; means for feeding a sliver of fibre through onepassage into said cavity for shredding by the related airstream andprojection of the shredded fibre against said peripheral surface as anevenly spread layer; and means for drawing spun yarn from said cavitythrough the other axial passage, said yarn growing by accretion at itsextremity engaging said surface through pick-up of fibre thereat, andsaid neutral pressure zone acting to separate said yarn from theincoming fibre.

4. A device for spinning yarn comprising a rotor having a cavitydefining two opposite parallel sides and a peripheral surface ofrevolution; means for rotating the rotor; the rotor having axialpassages of substantially the same diameter connected to said oppositesides thereof and communicating with said cavity; the rotor havingperipheral aperture means communicating with the cavity whereby rotationof the rotor will draw in air through both passages into said cavity anddischarge said air through said aperture means by centrifugal forcethereby creating opposed airstreams meeting on a transverse plane ofsaid cavity to establish thereat two boundary layers separated by aneutral pressure zone; means for feeding a sliver of fibre through onepassage into said cavity for shredding by the related air-stream andprojection of the shredded fibre against said peripheral surface as anevenly spread layer; said peripheral surface having a cross sectionalcontour tapered towards said one axial passage; and means for drawingspun yarn from said cavity through the other axial passage, said spunyarn growing by accretion at its extremity engaging said surface throughpick-up of fibre thereat, and said neutral pressure zone acting toseparate said yarn from the incoming fibre.

5. The device as claimed in claim 4, in which the end surface of saidcavity surrounding said other axial passage is provided with an annularrecess near the periphery thereof with said recess connecting with saidtapered peripheral surface via a surface section of inverse taper.

6. A device for spinning yarn comprising a rotor having a cavitydefining two opposite parallel sides and a peripheral surface ofrevolution; said peripheral surface having a smooth surface finish;means for rotating the rotor; the rotor having axial passages ofsubstantially the same diameter connected to said opposite sides thereofand communicating with said cavity; the rotor having pe ripheralaperture means communicating with the cavity whereby rotation of therotor will draw in air through both passages into said cavity anddischarge said air through said aperture means by centrifugal forcethereby creating opposed airstreams meeting on a transverse plane ofsaid cavity to establish thereat two boundary layers separated by aneutral pressure zone; means for feeding a sliver of fibre through onepassage into said cavity for shredding by the related airstream andprojection of the shredded fibre against said peripheral surface as anevenly spread layer; and means for drawing spun yarn from said cavitythrough the other axial passage, said spun yarn growing by accretion atits extremity engaging said surface through pick-up of fibre thereat,and said neutral pressure zone acting to separate said yarn from theincoming fibre.

7. A device for spinning yarn comprising a rotor having a cavitydefining a peripheral surface of revolution; means for rotating therotor; the rotor having axial passages connected to opposite sidesthereof and communieating with said cavity; said rotor having peripheralaperture means communicating with the cavity whereby rotation of therotor will draw in air through both passages into said cavity anddischarge said air through said aperture means by centrifugal forcethereby creating opposed airstreams meeting on a transverse plane ofsaid cavity to establish thereat a boundary layer; external blading forsaid rotor adjacent at least part of said aperture means for enhancingthe discharge of air therethrough; means for feeding a sliver of fibrethrough one passage into said cavity for shredding by the relatedairstream and projection of the shredded fibre against said peripheralsurface as an evenly spread layer; and means for drawing spun yarn fromsaid cavity through the other axial passage, said spun yarn growing byaccretion at its extremity engaging said surface through pick-up offibre thereat, and said boundary layer acting to separate said yarn fromthe incoming fibre.

8. A device for spinning yarn comprising a rotor having a cavitydefining a peripheral surface of revolution; means for rotating therotor; axially aligned stationary tubular nozzles projecting intocentral openings formed in opposite end walls of said rotor andcommunicating with said cavity; said rotor having peripheral aperturemeans communicating with the cavity whereby rotation of the rotor willdraw in air through said nozzles into said cavity and discharge said airthrough said aperture means by centrifugal force thereby creatingopposed airstrearns meeting on a transverse plane of said cavity toestablish thereat a boundary layer; means for feeding a sliver of fibrethrough one nozzle into said cavity for shredding by the relatedairstream and projection of the shredded fibre against said peripheralsurface as an evenly spread layer; and means for drawing spun yarn fromsaid cavity through the other nozzle, said spun yarn growing byaccretion at its extremity engaging said surface through pickup of fibrethereat, and said boundary layer acting to separate said yarn from theincoming fibre.

9. The device according to claim 7, including means for journalling saidrotor for rotation around at least one of said tubular nozzles.

10. A device for spinning textile fibres comprising a hollow rotorhaving two opposite parallel transverse walls and a side wall definingwith said transverse walls a cylindrical chamber, the diameter of whichchamber is substantially larger than the axial distance between saidtransverse walls, each of said transverse walls having a central openingand a plurality of angularly spaced air outlet openings between saidcentral opening and said side wall, means for feeding a fibre sliver toone central opening, means for withdrawing yarn through the othercentral opening, and means for driving said rotor at such rotationalspeed as to produce a boundary layer air flow over a portion of each ofsaid two transverse walls delimited by said outlet openings thereof toimpart to the axially incoming fibres suflicient rotary motion to havethe fibres projected against said side wall by the mere action ofcentrifugal force.

11. The device according to claim 10, in which said feeding meansinclude a stationary feed tube having one end extending through said onecentral opening, and in which said yarn withdrawing means include astationary delivery tube having one end extending through said othercentral opening, the inner diameter of said feed tube and of saiddelivery tube being substantially equal.

References Cited in the file of this patent UNITED STATES PATENTS2,808,697 Williams Oct. 8, 1957 2,853,847 Keeler et al Sept. 30, 1958FOREIGN PATENTS 1,111,549 Germany July 20, 1961 477,259 Great BritainDec. 24, 1937

1. A DEVICE FOR SPINNING YARN COMPRISING A ROTOR HAVING A CAVITYDEFINING TWO OPPOSITE PARALLEL FLAT SIDES AND A PERIPHERAL SURFACE OFREVOLUTION; MEANS FOR ROTATING THE ROTOR; THE ROTOR HAVING AXIALPASSAGES OF SUBSTANTIALLY THE SAME DIAMETER CONNECTED TO SAID OPPOSITESIDES THEREOF AND COMMUNICATING WITH SAID CAVITY; THE ROTOR HAVINGPERIPHERAL APERTURE MEANS COMMUNICATING WITH THE CAVITY WHEREBY ROTATIONOF THE ROTOR WILL DRAW IN AIR THROUGH BOTH PASSAGES INTO SAID CAVITY ANDDISCHARGE SAID AIR THROUGH SAID APERTURE MEANS BY CENTRIFUGAL FORCETHEREBY CREATING OPPOSED AIRSTREAMS MEETING ON A TRANSVERSE PLANE OFSAID CAVITY TO ESTABLISH THEREAT TWO BOUNDARY LAYERS SEPARATED BY ANEUTRAL PRESSURE ZONE; MEANS FOR FEEDING A SILVER OF FIBRE THROUGH ONEPASSAGE INTO SAID CAVITY FOR SHREDDING BY THE RELATED AIRSTREAM ANDPROJECTION OF THE SHREADED FIBRE AGAINST SAID PERIPHERAL SURFACE AS ANEVENLY SPREAD LAYER; AND MEANS FOR DRAWING SPUN YARN FROM SAID CAVITYTHROUGH THE OTHER AXIAL PASSAGE, SAID SPUN YARN GROWING BY ACCRETION ATITS EXTREMITY ENGAGING SAID SURFACE THROUGH PICK-UP OF FIBRE THEREAT,AND SAID NEURAL PRESSURE ZONE ACTING TO SEPARATE SAID YARN FROM THEINCOMING FIBRE.